What are the consequences of electing Donald Trump president? What will happen? What will President Trump actually do?

Based on what we've heard from Trump and his campaign over the past 18 months, as well as a close reading of experts like Evan Osnos of The New Yorker — who wrote a great article on the topic— here are some of my assumptions about a theoretical Trump presidency.

The smaller stuff:

President Trump will sign executive orders "erasing" as much of Obama's presidency as possible and tossing other bones to his supporters. These will likely include withdrawing the US from the Paris emissions accord, loosening background checks on people buying guns, restarting the Keystone Pipeline process, ordering investigations of trade practices, halting the flow of Syrian refugees, and more. (See Evan Osnos for more.)

President Trump will reinstate methods considered torture under international laws as intelligence-gathering tools. He will not call it "torture." He will describe it as the US finally getting tough ("an eye for an eye"). Trump will likely get pushback on this from senior intelligence and military officials. If the officials refuse to follow his order, Trump will fire them and replace them with generals and officials whose primary value is loyalty to Trump. President Trump will also appoint loyalists to as many of the 4,000 appointed positions he controls as possible.

President Trump will immediately "bomb the hell out of ISIS" — somewhere. This bombing may be no different than the bombing the US has been doing for years. President Trump will tout it as a major new offensive and extol its effectiveness and toughness. He will boast about this show of strength compared with the weakness and stupidity of the Obama administration. He will come to enjoy having the power to command the world's most powerful military.

President Trump will quickly work with Congress to "repeal Obamacare." If Congress blocks him on this, he will attack, shame, and bully key members publicly, while cutting deals behind the scenes. If President Trump is smart, he and his GOP allies will not actually repeal Obamacare because Americans like many features of it and because they have nothing to replace it with. They will just make changes to it that begin to fix some of its problems.

President Trump will continue to use the same rhetorical style he has used throughout the campaign. Namely, he will lie, bully, shame, exaggerate, insult, and otherwise throw prior concepts of acting presidential into the dumpster. After a few months of disgust and alarm, Americans and other citizens of the world will get used to this, just as they have his campaign rhetoric.

President Trump will also maintain the relationship to the truth that he has had throughout his campaign. Namely, he will cite actual facts and truth only when they help him. When the truth is inconvenient, President Trump will lie, deny, attack and threaten truth-tellers, speak in platitudes, and change the subject. The Trump administration will likely be one of the most secretive, most dishonest, and least transparent in modern history.

President Trump will reward "terrific" people and punish "terrible" people. The common attribute of "terrific" people will be that they support President Trump. The common attribute of the "terrible" people will be that they oppose President Trump. After a bruising election, President Trump will have lots of rewards to provide and scores to settle.

President Trump will announce that he is renegotiating NAFTA and other key US trade agreements and suspend potential participation in the Trans-Pacific Partnership. He will make minor changes to these trade deals and announce that he has replaced them with "great deals." He will tout any job growth that follows these changes as a direct result of these deals. President Trump will also likely slap high tariffs on Chinese imports to show that he is serious about "winning" and bringing jobs back. China will retaliate. The resulting limited trade war will likely be disruptive and bad for business in both countries. President Trump will say it is working great.

President Trump will personally unveil plans for his southern border wall. He will deliver the press conference announcing it and show scale models of it. Some sections of this wall may eventually be built. American taxpayers will pay for them. Trump will boast about how the wall is responsible for job creation and reduced crime. He will also increase the size of America's deportation force and tout the number of people it deports.

President Trump will propose $1 trillion of new spending on US infrastructure. Congress will support at least some of this. These projects will be unambiguously good for the country, even as they increase US federal debt. President Trump will also maintain Social Security and Medicare. He will pass a tax cut, of which most of the benefits will go to the wealthy. He will close the "carried interest tax loophole," which is one of the most egregious tax loopholes in the whole tax code. With the exception of the tax cut and deficit increase, all of these moves will be be good for America.

President Trump will never release his tax returns.

Thomson Reuters

The bigger stuff:

President Trump will mishandle a tricky geopolitical or military situation — with grave and potentially catastrophic consequences. Three obvious candidates involve the Middle East, North Korea, and China. The most likely candidate, meanwhile, is Russia. Trump will consider his personal relationship with Putin a higher priority than stopping Russia's territorial advances or supporting US allies. Putin already knows this and will take advantage of it. At some point, Putin will likely make a move into the rest of Ukraine or the Baltics. President Trump will either not respond, thus undermining NATO, or respond slowly or unwisely. He might also be so enraged by this personal betrayal by Putin that he might do something crazy, like nuclear saber rattling.

President Trump will try to modify the First Amendment and restrict freedom of the press. He will initially do this by rewarding supportive news organizations and reporters and savaging critical ones. If this does not stifle criticism of him or his administration, Trump will increase his harassment of critics by ordering investigations and encouraging supporters to boycott them. President Trump will call on his attorney general to threaten news organizations with criminal indictments and force them to turn over their sources. He will also do this on behalf of allies in Congress and organizations and people who support him, thus increasing support for actual changes in law.

President Trump will respond to terror attacks by barring Muslims from entering the country and increasing surveillance and profiling of Muslims in the US. If the attacks continue, President Trump will take another step, creating Muslim registration and/or camps in the US. President Trump will also respond to attacks by obliterating cities in Syria, Iraq, and other countries to punish "radical Islamic terrorists" and their families (and hundreds of thousands of other people). More broadly, President Trump's bigoted rhetoric will likely inflame racial and religious tensions in the US, leading to more violence and protests. For many Trump supporters, making America "great" again means making America "white and Christian" again, and even if President Trump does not actively support this, he'll do little to discourage it. (If the attack is just the usual generic US gun massacre, meanwhile, President Trump will extol the need for more guns for self-defense and tougher policing.)

President Trump will get impatient with the "checks and balances" on presidential power and try to expand the power of the presidency. If the economy stays solid and there are no major terrorist attacks or geopolitical crises, this will be difficult to do. If the economy deteriorates or there is a crisis, however, it will be easier. It is important to remember that, if elected, Trump will already have far more power and public support than famous dictators had when they came to power. (For example, see: "How Hitler went from a fringe politician to a dictator.")

Jim Young/REUTERS

Other consequences:

The stock market will drop 10-20% (for starters). A Trump presidency will significantly increase risk and uncertainty. That unnerves investors and business decision-makers. US companies will temporarily "freeze" plans while they try to figure out what President Trump is likely to do. This will likely temporarily slow economic growth. President Trump will blame the Obama administration for this and use it to demand emergency action from Congress. Trump's explicit attacks on many American companies — Ford, Amazon, Macy's, Nabisco, Apple — and promises to force some of these companies to move some manufacturing back to America will also unnerve decision-makers. Almost no major CEOs have supported Trump, and many have spoken out against him. These CEOs know that Trump will take this personally.

The fiscal deficit and debt will balloon. Trump's proposed tax cuts for the rich will not stimulate growth, just as the Bush tax cuts did not stimulate growth (because taxes on the wealthy are not actually stifling growth — what is stifling growth is the lack of middle-class spending power). The tax cut will, however, increase the deficit and accelerate the growth of federal debt. President Trump will blame this on Congress and the Obama administration.

At some point in President Trump's first term, there will be a major recession, and the stock market will drop 30-50% from the peak. President Trump's policies may well trigger this recession. Trade wars, for example, generally hurt economies and lead to job losses. Whatever happens, President Trump will blame it on his opponents and use it to try to expand his own power (see above). Widespread economic misery will make this easier.

Personally, I hope most of this doesn't happen. I hope that President Trump will be the president that some of his smarter supporters expect him to be — not the mean, petty, reckless, and uninformed proto-tyrant he sounds like, but a reasonable, effective pragmatist who just enjoys entertaining crowds by saying outrageous and offensive things and otherwise acting like a boor.

But given how consistent Trump has been in his actions and pronouncements over the past 18 months, I think it's more likely that what we've seen is what we will get.

This column does not necessarily reflect the opinion of Business Insider.